1. Field of the Invention
Aspects of the present invention relate generally to a broadband wireless communication system. More particularly, aspects of the present invention relate to an apparatus and method for estimating the size of a MAP for transmission of resource allocation information in a broadband wireless communication system.
2. Description of the Related Art
The fourth-generation (4G) communication systems (i.e., the next-generation communication systems) are intended to provide users with various Qualities of Services (QoS) with a data rate of about 100 Mbps. The 4 G communication systems are evolving to provide high mobility and high QoS in Broadband Wireless Access (BWA) communication systems, such as Local Area Network (LAN) systems and Metropolitan Area Network (MAN) systems. Typical examples of these communication systems are identified in the Institute of Electrical and Electronics Engineers (IEEE) 802.16 system standards.
The IEEE 802.16-based broadband wireless communication system uses an Orthogonal Frequency Division Multiple Access (OFDMA) scheme to provide broadband transmission. The OFDMA scheme uses a plurality of orthogonal subcarriers to transmit data. The OFDMA scheme is robust against multipath fading and has high spectral efficiency, thus providing high throughput in high-rate data transmission. Generally, the broadband wireless communication system groups all orthogonal subcarriers into subchannels. The broadband wireless communication system also performs communication on a frame basis. A Base Station (BS) may transmit a MAP message including information about data bursts allocated in each frame, and a user terminal may decode the MAP message to detect the burst allocation state.
The broadband wireless communication system may use a frequency reuse pattern of 1 or N (>1). If the frequency reuse pattern is 1, all cells may use all subchannels in common. In this case, the spectral efficiency may increase, but the reception performance of a user terminal may degrade due to the co-channel interference between adjacent cells if the user terminal is located at a cell boundary. On the other hand, if the frequency reuse pattern is 2 or more, adjacent cells may use different subchannels. In this case, the reception performance of a user terminal may improve, but the spectral efficiency may decrease. Thus, applying a frequency reuse pattern of 1 to user terminals with good reception environments is necessary to increase the spectral efficiency, and applying a frequency reuse pattern of N (>1) to user terminals located at cell boundaries is necessary to reduce the interference between adjacent cells. What is therefore needed is a scheme for applying the frequency reuse pattern flexibly according to the reception environments of user terminals.
The base station also specifies data burst allocation information of a user terminal in a downlink (DL) MAP region of a DL frame. A plurality of time slots are used to allocate the data bursts in the DL data period. The BWA communication system standard (i.e., the IEEE 802.16 spec) specifies that the base station records resource allocation information in a MAP region with a fixed size when allocating DL resources. In other words, the base station uses a fixed number of DL MAP Information Elements (IEs) to determine the size of a data burst allocation region and the number of data bursts to be allocated, thus degrading the resource utilization and efficiency.